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Figure 4. Developmental expression and alternative splicing activity of Celf1 are conserved in Xenopus laevis. Celf1 protein was evaluated in whole embryo extracts (A) and isolated hearts (B) by Western blot analysis. Blots were stripped and reprobed for Gapdh or γ-Tubulin. Protein integrity and equivalent loading were also confirmed by Ponceau S staining. C: celf1 transcript levels were evaluated in embryonic and adult hearts (n = 3–4) by real-time RT-PCR. Error bars indicate 95% confidence intervals. A one-way analysis of variance found no significant differences in celf1 between the stages. Celf1 was visualized by immunofluorescence in the whole embryonic heart (D, left) and heart sections (D, right), skeletal muscle (E), eye (F), and neural tube (G). A, atrium; V, ventricle; OFT, outflow tract; myo, myocardium; RBC, red blood cell; N, notochord; NT, neural tube. H: The CELF-responsive RTB33.51 mini-gene was co-expressed in COSM6 cells with celf1-a, RNA was collected 72 hr later, and alternative splicing was assessed by radiolabeled RT-PCR (top). Celf1 expression was confirmed by Western blot analysis (WB). Lanes shown are from the same gels; intervening lanes were removed for clarity. *P ≤ 0.01; vs. mini-gene alone as evaluated by Student's t-test. |
